1. Field of the Invention
The invention relates to a supporting device of a transport device of a soldering apparatus for the conveying of printed-circuit boards with at least two revolving, endless transport chains, said transport chains running in guide rails in the transport zone and each passing through two guide elements at the ends of the transport zone, wherein, for adaptation to the width of the respective printed-circuit boards, the guide elements are mounted on a carrier such as to be displaccable transverse to the conveying direction.
2. Description of Background Art
Generally, in supporting devices of transport devices in soldering apparatuses for the conveying of printed-circuit boards, there is a high thermal loading at least in the transport zone. Thus, temperatures up to 300° C. Or above are perfectly customary in the transport zone. Such high temperatures lead to material-induced thermal expansion of the elements of the supporting device of the transport device. Such thermal expansion, which varies for the different elements of the supporting device of the transport device depending on the mass, geometry and material thereof, is, in the prior art, accommodated and/or compensated by appropriate adjusting means or supports, this resulting in the prior art in a high degree of structural complexity. This high degree of structural complexity, however, is necessary in order always to guarantee the reliable transport of the printed-circuit boards under all operating states, i.e. including in the case of different temperatures in different sections of the transport zone. More particularly, it is necessary, in the prior art, for the guide rails—in which run the endless transport chains in the transport zone—to be, where possible, in the form of individually mounted rail segments which, also in the case of thermal expansion, can be kept in alignment with each other through appropriate adjustability of the mountings and through the arrangement of expansion joints between the segments, the intention being to prevent vertical and horizontal deflection of the rail segments. However, even this high degree of design complexity with adjustable individual mounting of rail segments is not always able to ensure completely reliable guiding, particularly where there are temperature differences in different sections along the transport zone, because the necessary tolerances, especially of the expansion joints, are easily exceeded.